Research Core: Clinical Core Abstract The foundation of the clinical core is an interactive registry of ANCA glomerulonephritis (GN) patients which allows long-term patient follow-up and biological sample collection. Our inception cohort now includes 868 patients followed prospectively from diagnosis throughout their disease course and life until death. Our clinical core has an extremely successful record of retention and follow up manifested by exceeding enrollment goals and patient retention for the currently funded Projects. Organization of protocol visits and serial samples with clinical data collection allows orchestration of patient based scientific research that would otherwise not be possible. Rich variety in patient presentation and response to disease and therapy allows this inception cohort to supply vital samples across the presentations of ANCA GN. The Core ensures adequate sample sizes and appropriate recruitment for projects 1, 2 and 4 as well as providing statistical programming, analyses and interpretation for all projects. The Core has successfully supported this Program Project with participation in numerous publications related to specific aims and specific projects. The Core has also gained an outstanding reputation for mentoring and collaborative research. We have shared de-identified data to maximize the research potential of the cohort and have collected new data or recruited patients from our cohort for studies outside of this Program Project. The efforts of the Core sustain the proposed projects, and our collaborative efforts have led to innovative research that continually brings new ideas, new investigators and overall enthusiasm to the ANCA research community.